This invention relates generally to the detection of the human body by the reflection of near-infrared bands when the body is exposed to near-infrared illuminator, and more specifically to an automatic detection method of a human body under conditions which the body is not discernable by the unaided eye. Typical environments in which the detecting methods and devices are envisioned lie in the specific areas of persons lost at sea, in the forest, the desert, or in the artic regions where visual search aids do not readily acquire the identity and position of such persons. Other environments envisioned are those areas to be secured from intruders.
In a situation where a human body is in a night-time or darkened environment or in a concealed surrounds but a portion or segment of the skin is not obscured, methods for uniquely locating a human body has not been fully sucessful. Methods such as thermal viewers where the body heat radiation is detected, the position of the body becomes known but identification of the body with respect to similar heat radiating sources is unique. A recognition pattern signiture is required to identify the body, i.e., face, hands, torso, etc. for unique determination of the heat source as human. If the body should be deceased but not decomposed, the thermal viewer does not "see" the body since the thermal emission characteristics of the body would become in thermal equilibrium with the surrounds. In such cases the thermal viewer is not readily effective. The present method employs a near-infrared illumination-reflection technique which uniquely detects and identifies an object as a human body or portion of the body surface (skin) when such an object is unobscured to the illuminator-detector device.